Acute and chronic respiratory illness represent a substantial proportion of childhood disease burden in the United States. Approximately 16% of admissions to U.S. children's hospitals are secondary to respiratory disease. Significant gaps exist between evidence-based clinical practice guidelines and the health services provided to the nation's youth. Results of the first comprehensive evaluation of outpatient pediatric quality of care found U.S. children on average receive only 46% of recommended care; just 45% of recommended care for asthma was received. No similar data exist for hospitalized children. While this level of adherence to standards for ambulatory care is disturbing, the impact of poor quality of care on hospitalized children, especially those at increased risk for respiratory failure, is likely to have more serious consequences. Our main objectives are to develop a rigorously designed quality of care assessment tool that can be used to examine the degree to which hospitals caring for children are adhering to recommended standards of care for respiratory illness and to determine the feasibility and validity of using administrative data to make these assessments. Specifically, we will use the RAND/UCLA modified Delphi method to develop a quality of care assessment tool for pediatric respiratory illness. We will then use the tool to conduct a detailed assessment of inpatient management for children treated for six respiratory conditions: asthma, bronchiolitis, croup, pneumonia, congenital lung malformations, and cystic fibrosis. The tool developed will be structured to generate quality scores using medical records data. First, we will conduct a detailed assessment of the inpatient management of 3,000 children admitted to three U.S. children's hospitals: Cincinnati Children's Hospital Medical Center, Children's Hospital Los Angeles, and Seattle Children's Hospital and Regional Medical Center. Second, we will examine the comparability of quality scores obtained using medical records versus administrative data for quality measurement. Finally, we will examine the relationship between quality scores and child health related quality of life to outcome-validate our quality assessment tool. This study will result in a rigorously designed, disseminable quality assessment tool that can be used by hospitals treating children for respiratory illness to both track and improve on the quality of care they provide.